Influenza A virus (IAV) remains a major threat to human health because of its ability to continually change its surface proteins and evade adaptive immunity. This project addresses key aspects of the innate immune response that provide initial protection of the lung against novel IAV strains. Understanding these innate immune responses may explain why some people suffer severe illness with IAV infection or why pandemic IAV strains are more pathogenic than seasonal strains. For example, our recent findings indicate that pandemic IAV strains evade neutralization by important innate immune mediators, including the surfactant proteins A and D (SP-A and SP-D) and anti-microbial peptides (AMPs) like LL-37, defensins and histones. We have sought to exploit understanding of the mechanisms of action of innate immune proteins to develop modified forms of these proteins with increased antiviral activity. We have thus far shown that mutated versions of SP-D, and modified synthetic peptide derived from LL-37, gain the ability to inhibit pandemic IAV.
In Aim 1, we will determine at a molecular level how SP-D binds to the IAV hemagglutinin (HA) in order to explain how pandemic IAV evades neutralization and also how our novel mutated forms of SP-D can overcome this and neutralize IAV. SP-A differs from SP-D in that it neutralizes the virus by providing a decoy sialic acid ligand for the HA to bind to.
In Aim 2, we will determine why pandemic IAV is resistant to SP-A but sensitive to some other inhibitors (e.g., H-ficolin) that have similar mechanisms of antiviral activity.
In Aim 3, similar studies will be done regarding the AMPs with emphasis on LL-37, which does not inhibit pandemic IAV, and the LL-37 derived peptide which does inhibit it. Finally, Aim 4 will explore how the different proteins modulate inflammatory responses to IAV to reduce potentially harmful inflammation (SP-D, SP-A or LL-37) or possibly increase it (histones) in vitro and in vivo. Key techniques for the proposal will include mass spectroscopy of viral membrane glycoproteins (e.g., HA), xray crystallography and molecular modeling, reverse genetics to generate modified viral strains, and in vitro and in vivo viral infection assays. Our collaborators are prominent experts in glycoproteomics and protein structure analysis and together we have developed powerful techniques to understand the molecular basis for viral neutralization by innate proteins at a level of precision not previously achieved. These studies should enable us to develop additional viral inhibitors through structurally informed modification of collectins (SP-A and SP-D) or AMPs.

Public Health Relevance

Influenza viruses cause approximately 40,000 deaths each year in the USA and there is high likelihood that new pandemic viruses will emerge that can cause much greater illness and death. This project attempts to explain how the body usually protects itself against infection with new influenza strains during the first few days of infection and why some people or groups of people are more vulnerable to severe illness with the flu. There is a great need for more effective treatments for influenza and the long range goal of this project is to use understanding of how the body natural protects itself to develop new therapies for the flu.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL069031-14
Application #
8886541
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Harabin, Andrea L
Project Start
2001-12-12
Project End
2019-06-30
Budget Start
2015-07-01
Budget End
2016-06-30
Support Year
14
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Boston Medical Center
Department
Type
DUNS #
005492160
City
Boston
State
MA
Country
United States
Zip Code
White, Mitchell R; Kandel, Ruth; Hsieh, I-Ni et al. (2018) Critical role of C-terminal residues of the Alzheimer's associated ?-amyloid protein in mediating antiviral activity and modulating viral and bacterial interactions with neutrophils. PLoS One 13:e0194001
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Khatri, Kshitij; Klein, Joshua A; White, Mitchell R et al. (2016) Integrated Omics and Computational Glycobiology Reveal Structural Basis for Influenza A Virus Glycan Microheterogeneity and Host Interactions. Mol Cell Proteomics 15:1895-912
Hsieh, I-Ni; Hartshorn, Kevan L (2016) The Role of Antimicrobial Peptides in Influenza Virus Infection and Their Potential as Antiviral and Immunomodulatory Therapy. Pharmaceuticals (Basel) 9:
Hoeksema, Marloes; van Eijk, Martin; Haagsman, Henk P et al. (2016) Histones as mediators of host defense, inflammation and thrombosis. Future Microbiol 11:441-53
Tripathi, Shweta; White, Mitchell R; Hartshorn, Kevan L (2015) The amazing innate immune response to influenza A virus infection. Innate Immun 21:73-98
Tripathi, Shweta; Wang, Guangshun; White, Mitchell et al. (2015) Identifying the Critical Domain of LL-37 Involved in Mediating Neutrophil Activation in the Presence of Influenza Virus: Functional and Structural Analysis. PLoS One 10:e0133454
Hoeksema, Marloes; Tripathi, Shweta; White, Mitchell et al. (2015) Arginine-rich histones have strong antiviral activity for influenza A viruses. Innate Immun 21:736-45

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